It is disposed in WO2012/077450A1 to connect, as a conventional internal resistance measuring device of a laminated battery, a source line and a sense line to a separator of a laminated battery in different paths. This conventional internal resistance measuring device of the laminated battery has measured an internal resistance of the laminated battery by causing an alternating current to flow in a power generation region of the separator via the source line and inputting an alternating-current potential at that time to the internal resistance measuring device via the sense line.